Protector.



D. T MAY. PROTECTOR.

APPLICATION FILED JAN.1E,1915.

Patented Mar. 20, 1917.

- dielectric material such as mica.

UNITED STATES PATENT OFFICE.

DAVID T. MAY, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

PROTECTOR.

Specification of Letters Patent.

Patented Mar. 20, 1917.

Application filed January 16, 1915. Serial No. 2,676.

To (1115 whom it may concern:

Be it known that I, DAVID T. MAY, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful ImproX'ements in Protectors, of which the following is a full, clear, concise, and exact description.

This invention relates to protective devices for electric circuits.

111 the protective devices commonly used in practice, it has been customary to separate the electrodes thereof by means of a The trouble experienced in the past by using such a material as a spacing medium has been that it is very diiiicult to hold the mica to a required thickness, especially in a protector provided with a very small air gap between the electrodes. It is the object of this invention to provide a protective device in which this difficulty is overcome by making it unnecessary to separate the electrodes thereof by the intervention of a dielectric material.

One' form of a protector made in accordance with the features of this invention may comprise a pair of electrodes, preferably metallic, positioned to oppose each other, one of which is mounted in a non-conducting base-or body portion, while the other of said electrodes is separated from said first-mentioned electrode by means of a spacing medium such as strips of metal.

In another form of a protective device comprising a modification of this invention, there is provided a pair of electrodes one of which has portions thereof removed, and a non-conducting material inserted therein, said electrodes being separated by metallic strips placed between them at the point where said insertions were made.

This invention is illustrated by the accompanying drawing in which,

Figure l is a front elevation, partly 1n section, of a protector embodying the features of this invention;

Fig. 2 is an end elevation of the device as shown in Fig. 1;

Fig. 3 is a front elevation, partly in section, of a modified form of the device shown in Figs. 1 and 2; and

Fig. 4 is'an end elevation of the modlfied device shown in Fig. 3.

A protector embodying the features of this invention is comprised of a pair of electrodes 5 and 6 positioned to oppose each other, being retained in this relation by means of dowel pins 7, 7. The electrode 5 may consist of a metallic bar or plate, while the electrode 6 may be of like material considerably smaller than electrode 5 and embedded in a plate of glass 8 or some other non-conducting substance, the two plates corresponding in size. The opposing surface of the plate 8 and the surface of the electrode 6 are ground flush with each other, or otherwise made to lie in the same plane. For more securely retaining the electrode 6 in a fixed position, said electrode is shaped substantially as shown and in case the nonconducting plate 8 happens to be made of glass said electrode is embedded therein when said glass is in a molten condition.

To separate the'electrodes 5 and 6 there are provided metallic strips 9, 9, the ends of which are inserted in suitable slots 10, 10 out diagonally at the corners of the outside surface of the electrode 5, and held in position by soldering or otherwise suitably fastened. It will be noted that the metal strips 9, 9 can'be made of considerably less thickness than it is possible to make a dielectric, such as mica, and at the same time preserve the uniformity and strength required to give satisfactory service. The strips 9, 9 by being inserted between the electrode 5 and the nonconducting plate 8, separate the electrodes 5 and 6 and at the same time keep them insulated from each other.

In the modification shown in Figs. 3 and 4, the electrodes 11 and 12 are comprised of metallic plates one of which (for example plate 11) has a portion removed at the ends thereof and a n0n-conducting material 13, such as fiber, inserted therein. In this form of a protector the metallic strips 9, 9 are placed between the electrodes 12 and the points where the non-conducting material inserts 13 have been'made.

From the above it will be apparent that by the means provided in this invention a protector may be constructed in which it is commercially possible to regulate toamarked degree of fineness, the air gap desired between the electrodes thereof, and do so without the intervention of a dielectric materlal.

What is claimed is: V

1. A protector comprising a bodyof 1nsulating material, an electrode posltioned therein, an opposing electrode, and metallic means inserted between said insulating material and opposing electrode for spacing said electrodes apart.

2. A protector comprising a body of insulating material, an electrode positioned therein, an opposing electrode, and a nonheat softenable means inserted between said insulating material and opposing electrode for spacing said electrodes apart.

3. A protector comprising a pair of opposing electrodes separated by an air gap, at non-conducting material forming a part of the body portion of one of said electrodes, the other of said electrodes comprising a metallic member and metallic spacing means for maintaining said air gap, said means being inserted betyqeen said metallic member and said non conducting material.

4. A protector comprising a block of conducting material, an opposing block comprising bodies of conducting and insulating material, and ametallic spacing member being between said first mentioned block and the insulating body of the said second block.

5. An electrode for a protector comprising a conducting body portion, and metallic strips secured in slots formed in the ends of said body portion.

In Witness whereof, I hereunto subscribe my name this 15th day of January, A. D, 1915.

DAVID '1. MAY.

Witnesses:

E. EDLER, K. L. STAIIL. 

